The present invention relates to a key press switch for an electronic piano to detect a key press motion.
It is well known that when a key press occurs in an acoustic piano, static touch characteristics (in the case of a grand piano) as shown in FIG. 5 are obtained in connection with a load applied to the pressed key by an operation of an action caused by the key press.
An electronic piano without an action mechanism as in an acoustic piano is provided with a pseudo action mechanism to thereby achieve, when a key press occurs, static touch characteristics similar to those to be obtained by an acoustic piano.
For example, the electronic piano is provided with a let-off member 6, as shown in FIG. 6, as a member constituting the pseudo action in order to obtain a let-off feeling that is included in the static touch characteristics of an acoustic piano.
In the electronic piano provided with the let-off member 6, a pseudo hammer 5 is raised when a key is pressed, and an engaging projection 27 attached to the pseudo hammer 5 contacts the let-off member 6 at a timing when a let-off should occur. Then, a let-off feeling will be provided (see Japanese Unexamined Patent Application Publication No. 2010-262129).